<template>
    <div>
      <hr />
      <h1>{{ title }}</h1>
      <button @click="$emit('update:title', '子组件的数据 200')">修改数据</button>
      <hr />
    </div>
  </template>
  
  <script>
  export default {
    props: ["title"],
  };
  </script>
  
  <style></style>
  